Unfolding parabolic antenna



March 24, 1970 H. G. THOMPSON 3,

UNFOLDING PARABOLIC ANTENNA Filed June 28, 1967 3 Sheets-Sheet lINVENTOR HORACE G. THOMPSON BY ymmh W ATTORNEYS March 24, 1970 THOMPSON3,503,072

UNFOLDING PARABOLIC ANTENNA Filed June 28, 1967 3 Sheets-Sheet 2 INVENTOR HORACE 6. THOMPSON M al 0% ATTORNEYS March 24, 1970 H. c. THOMPSON 3,

UNFOLDING PARABOLIC ANTENNA Filed June 28. 1967 3 Sheets-Sheet 5 INVENTOR.

HORACE G. THOMPSON M w; ATTORNEYS United States Patent O 3,503,072UNFOLDING PARABOLIC ANTENNA Horace G. Thompson, Accokeek, Md., assignorto the United States of America as represented by the Secretary of theNavy Filed June 28, 1967, Ser. No. 650,160 Int. Cl. H01q 19/12 US. Cl.343-705 8 Claims ABSTRACT OF THE DISCLOSURE An unfolding antenna forradar scanning and especially suited for use aboard satellites and otherspace vehicles. The antenna is structurally formed of panels which areunfolded from stowed to extended position by energy from compressed gas.

BACKGROUND OF THE INVENTION Field of the invention The present inventionrelates to an unfolding type antenna and more particularly to an antennawhich is structurally formed of panels that are compactly folded in astowed position and which are forced to an extended position by energyfrom compressed gas. The invention is particularly suited for use withradar aboard satellites and other space vehicles.

Description of the prior art In the past decade the technical spacecapability has increased rapidly and is now at a point where large orbitand space probe vehicles are feasible. These nowfeasible large vehiclesallow the use of electronic systerns, such as scanning radar, thatrequire large antennas for optimum performance. For obvious reasons,these large antennas must be compactly stowed during the launchingperiod and later deployed when the vehicle is in space.

Several systems for deploying large antennas in space have beendeveloped. These systems are not entirely satisfactory because theseknown systems use electric motors with inherent disadvantages relatingto weight and electric power requirements. Another, notquite so obvious,disadvantage of these prior systems is that the deployment motorsintroduce large reaction torques which tend to disturb the stabilizedspace vehicles.

SUMMARY OF THE INVENTION The general purpoese of this invention is toprovide a large antenna which can be deployed in space and whichembraces all of the advantages of similarly employed prior antennasystems and possesses none of the aforedescribed disadvantages. Toattain this, the present invention contemplates a large antenna which isstructurally formed of seven joined panels and which is deployed inspace, from a compactly stowed position, by the energy of compressedgas.

It is, therefore, an object of this invention to provide an improvedlarge antenna which can be deployed in space.

Another object is the provision of an improved large antenna which canbe deployed in space by the energy of compressed gas.

A still further object of the invention is to provide an improved largeantenna which can be deployed in space by the energy of compressed gasand which is structurally formed of seven joined panels.

BRIEF DESCRIPTION OF THE DRAWING Other objects and advantages of theinvention will hereinafter become more fully apparent from the fol-3,503,072 Patented Mar. 24, 1970 "ice DESCRIPTION OF THE INVENTIONReferring now to the drawings, wherein like reference charactersdesignate like or corresponding parts throughout the several views,there is shown in FIG. 1 the antenna 10 of the invention in the fullydeployed state. The antenna 10 is formed as a parabolic cylinderreflector and typically could be 24 feet across and 40 inches high andsuitable for use with L-band scanning radar.

Seven panels, preferably formed of any strong, electromagneticallysuitable lightweight-sandwich material, comprise the reflector. Asillustrated the curved central panel 12 is hinged on opposite sides tocurved panels 14 and 16 which are in turn hinge connected to curvedpanels 18 and 20. These latter panels are also respectively hingeconnected to the outer curved panels 22 and 24.

Telescoping struts 26 and 28 are respectively hinge connected to theouter ends of panels 14 and 16. These struts are also hinge connected toyoke 30 which is rigidly connected to one end to center panel 12 and onthe other end to the slotted feed 32. The functional purpose of thecompressed gas operated struts 26 and 28 will subsequently be described.

Flexible lines 34 and 36, preferably made of fiberglass, are connectedbetween feed assembly 32 and the center of panels 22 and 24. Similarlines 38 and 40, which for purposes of drafting simplicity are shownonly in FIGS. 4 and 5, are connected along the reverse side of thereflector and across hinged links 42 and 44, as shown, between thecenter panel 12 and the center of outer panels 22 and 24.

Referring now to FIG. 2, the antenna 10 is shown in the stowedcondition. For the typical dimensions previously mentioned, theinvention requires a stowing space 3 by 4 by 9 feet. In FIG. 2, forpurposes of clarity, the lines 34 and 36 are omitted.

FIGS. 3, 4 and 5 show the progressive deployment of antenna 10 from thestowed position shown in FIG. 2 to the fully deployed positionillustrated in FIG. 5. This deployment is accomplished by the energy ofcompressed gas which is carried in and released in and then causes theextension of the telescoping struts 26 and 28. It can be seen from FIGS.2-5 that the extension of the struts 26 and 28 and the restraintexercised by lines 34 and 36 cause the panels 14, 16, 18, 20, 22, and 24of the antenna 10 to gradually transform from the very narrow W shape ofthe stowed position shown in FIG. 2 to the progressively wider W shapesof FIG. 3 and 4 and finally to the fully deployed parabolic cylindershape of FIG. 5. This gradual transformation occurs about the rigidassembly of panel 12, yoke 30 and feed 32 which provides a strongbackbone for the entire antenna.

The lines 38 and 40, which are connected to panel 12 and hinged links 42and 44, are provided to prevent the outer panels 22 and 24 from swingingtoo far forward under the urging forces exerted by the telescopingstruts 26 and 28 and the lines 34 and 36.

It is apparent from the drawings that the reaction forces arising in theextension of the struts 26 and 28 and the accompanying deployment of theantenna 10 will be largely self-cancelling since the struts extend indirections which are nearly opposite. The self-cancellation of thedeployment forces is an advantageous feature of the invention,especially where the antenna is used on a space vehicle, since thedisturbance to the stability of the space vehicle, particularly in thedirection of flight, is minimized.

The contemplated environment of the antenna 10, although it will beeasily appreciated that the invention is not limited to suchapplication, is on board a satellite or space probe. During thelaunching the antenna is stowed inside the space vehicle and at theappropriate time is moved to the exterior of the vehicle by means whichare not a part of the invention. The typical antenna previouslydimensionally described weighs under 65 pounds and is moved from theinside to the outside of a space vehicle through a hatch opening of 3.2by 42 inches.

After the antenna is outside the space vehicle, the compressed gas isreleased by some control means which is not a part of the invention buttypically could be electrically controlled valves. The antenna is thendeployed by the energy of the released compressed gas, but, aspreviously mentioned the deployment forces will be largelyself-cancelling and therefore will not disturb the sta bility of thespace vehicle. Subsequently the antenna 10 is used as desired, forexample, with scanning L-band radar in which event the antenna isrotated by some mechanism which is connected to the yoke 30.

There has been disclosed an improved large antenna which can be deployedin space by the energy of compressed gas and which is structurallyformed of seven joined panels. Additional, more detailed, informationconcerning the invention may be found in NRL Report 6480, published Dec.28, 1966 by the Naval Research Laboratory, Washington, DC and titled AnUnfolding Mechanically Scanned Antenna for a Satellite-Borne Radar.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood, that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

What is claimed and desired to be secured by Letters Patent of theUnited States is:

1. An antenna for use with a space vehicle comprising:

a yoke attached to said vehicle;

an antena feed rigidly connected to said yoke;

a rectangular central panel rigidly connected to said yoke;

at least one side panel hinge connected to each of the opposite longersides of said rectangular central panel and first and second telescopingstrut means hinge connected respectively between said yoke and said sidepanels, said first and second telescoping strut means being extensiblyenergized for moving said side panels from a folded, stowed state to adeployed state wherein said central panel and said side panels form aparabolic cylinder shaped reflector,

2. An antenna as set forth in claim 1 wherein said extensibleenergization is accomplished by the release of compressed gas withinsaid first and second telescoping strut means.

3. An antenna as set forth in claim 2 wherein said first and secondtelescoping strut means face in substantially opposite directions.

4. An antenna as set forth in claim 3 and further including flexibleline means connected between said side panels and the rigidly connectedassembly of said yoke, said central panel and said feed for limiting themovement of said side panels to the deployed state.

5. An antenna for use with a space vehicle comprising:

a yoke attached to said vehicle;

an antena feed rigidly connected to said yoke;

a rectangular central panel rigidly connected to said yoke;

a first plurality of curved side panels hinge connected to each otherand to one of the longer sides of said rectangular central panel;

a second plurality of curved side panels hinge connected to each otherand to the other of the longer sides of said rectangular central paneland first and second telescoping strut means hinge connectedrespectively between said first and second pluralities of curved sidepanels and said yoke, said first and second telescoping strut meansbeing extensibly energized for moving said first and second plurality ofcurved side panels from a folded, stowed state to a deployed statewhereinsaid central panel and said side panels form a parabolic cylindershaped reflector.

6. An antenna as set forth in claim 5 wherein said extensibleenergization is accomplished by the release of compressed gas withinsaid first and second telescoping strut means.

7. An antenna as set forth in claim 6 wherein said first and secondtelescoping strut means face in substantially opposite directions.

8. An antenna as set forth in claim 7 and further including flexibleline means connected between the rigidly connected assembly of saidyoke, said central panel and said feed and said first and secondpluralities of curved side panels for limiting the movement of said sidepanels to the deployed state.

References Cited UNITED STATES PATENTS 2,945,234 7/1960 Driscoll 3439 15FOREIGN PATENTS 216,556 5/1969 Switzerland.

ELI LIEBERMAN, Primary Examiner US. Cl. X.R.

